1. Field
One or more embodiments relate to a robot cleaner that travels straight through alignment of drive wheels and a method of controlling travel of the same.
2. Description of the Related Art
Generally, a robot cleaner is an apparatus that travels in a cleaning area without user manipulation to suction foreign matter such as dirt from a floor, thereby performing cleaning.
Cleaning a cleaning area using such a robot cleaner entails the robot cleaner repetitively performing cleaning while moving in a predetermined travel pattern. The travel pattern may include a right-angle travel pattern and a random travel pattern. In the right-angle travel pattern (zigzag travel pattern), the robot cleaner turns 90 degrees and then travels straight when the robot cleaner comes across an obstacle (for example, a wall) after straight travel. In the random travel pattern, the robot cleaner turns to an arbitrary direction and then travels straight when the robot cleaner comes across an obstacle (for example, a wall) after straight travel.
A pair of drive wheels are mounted at opposite sides of a lower part of a cleaner body of the robot cleaner to move the cleaner body such that the robot cleaner travels straight. When the robot cleaner travels on a hard floor, such as a wooden floor or a vinyl floor, slippages of the drive wheels are similar to each other, with the result that a rate of rotation of one of the drive wheels is similar to a rate of rotation of the other drive wheel, whereby the robot cleaner easily travels straight. On the other hand, when the robot cleaner travels on a carpet in a state in which texture of the carpet occurs in one direction, slippages of the drive wheels are different from each other, with the result that the robot cleaner does not travel straight but swerves often. In particular, when the texture of the carpet is severe, or the carpet pile is short, slippages of the drive wheels 21 and 22 increase, with the result that the robot cleaner swerves.
To prevent the robot cleaner from swerving, track shapes or materials of the drive wheels have been changed to reduce slippages of the drive wheels. However, such design is limited. For example, when the drive wheels are designed to have protrusions like a snow tire, slippages of the drive wheels may be prevented to some extent on a carpet; however, on a hard floor, the drive wheels may have low contact force with the floor and may be easily worn.